Surgical instrument and loading unit for use therewith

ABSTRACT

A surgical instrument is disclosed. The surgical instrument includes a handle assembly, a drive assembly, an endoscopic portion, a pair of jaw members, a dynamic clamping member, and a tissue stop. The drive assembly is disposed in mechanical cooperation with a movable handle of the handle assembly. The endoscopic portion defines a first longitudinal axis. The jaw members are each longitudinally curved with respect to the longitudinal axis. The dynamic clamping member is disposed in mechanical cooperation with a distal portion of the drive assembly and includes an upper beam, a lower beam, and a vertical beam having a cutting edge on a distal portion thereof. At least a portion of the dynamic clamping member is longitudinally curved with respect to the longitudinal axis. The tissue stop is disposed adjacent a distal portion of the first jaw member and configured to impede tissue from distally escaping the jaw members.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.13/177,708 filed Jul. 7, 2011, now U.S. Pat. No. 8,267,302, which is acontinuation of U.S. application Ser. No. 12/553,174 filed Sep. 3, 2009,now U.S. Pat. No. 7,988,028, which is a continuation-in-part and claimsthe benefit of U.S. application Ser. No. 12/235,751, filed Sep. 23, 2008now U.S. Pat. No. 7,896,214, and the disclosures of each of theabove-identified applications are hereby incorporated by reference intheir entirety.

BACKGROUND

1. Technical Field

The present disclosure relates generally to instruments for surgicallyjoining tissue and, more specifically, to surgical instruments havingcurved jaw members and loading units for use therewith.

2. Background of Related Art

Various types of surgical instruments used to surgically join tissue areknown in the art, and are commonly used, for example, for closure oftissue or organs in transection, resection, anastomoses, for occlusionof organs in thoracic and abdominal procedures, and forelectrosurgically fusing or sealing tissue.

One example of such a surgical instrument is a surgical staplinginstrument, which may include an anvil assembly, a cartridge assemblyfor supporting an array of surgical staples, an approximation mechanismfor approximating the cartridge and anvil assemblies, and a firingmechanism for ejecting the surgical staples from the cartridge assembly.

Using a surgical stapling instrument, it is common for a surgeon toapproximate the anvil and cartridge members. Next, the surgeon can firethe instrument to emplace staples in tissue. Additionally, the surgeonmay use the same instrument or a separate instrument to cut the tissueadjacent or between the row(s) of staples.

SUMMARY

The present disclosure relates to a surgical instrument for surgicallyjoining tissue. The surgical instrument includes a handle assembly, adrive assembly, an endoscopic portion, a pair of jaw members, a dynamicclamping member, and a tissue stop. The drive assembly is disposed inmechanical cooperation with a movable handle of the handle assembly. Theendoscopic portion defines a first longitudinal axis. The jaw membersare each longitudinally curved with respect to the longitudinal axis.The dynamic clamping member is disposed in mechanical cooperation with adistal portion of the drive assembly and includes an upper beam, a lowerbeam, and a vertical beam having a cutting edge on a distal portionthereof. At least a portion of the dynamic clamping member islongitudinally curved with respect to the longitudinal axis. The tissuestop is disposed adjacent a distal portion of the first jaw member andconfigured to impede tissue from distally escaping the jaw members.

The present disclosure also relates to a loading unit configured forreleasable engagement with a surgical instrument. The loading unitcomprises a body portion, a drive assembly, a pair of jaw members, adynamic clamping member, and a tissue stop. The body portion defines alongitudinal axis. A proximal portion of the body portion is configuredfor releasable engagement with an endoscopic portion of the surgicalinstrument. The drive assembly is slidingly disposed at least partiallywithin the proximal body portion. The pair of jaw members extendsgenerally distally from the proximal body portion and each of the jawmembers is longitudinally curved with respect to the longitudinal axis.At least one of the jaw members is movable with respect to the otherbetween an open position and an approximated position for engaging bodytissue therebetween. The pair of jaw members includes a first jaw memberand a second jaw member. The dynamic clamping member is disposedadjacent a distal portion of the drive assembly and includes an upperbeam, a lower beam, and a vertical beam. The vertical beam connects theupper beam and the lower beam and includes a cutting edge on a distalportion thereof. The vertical beam is longitudinally curved with respectto the longitudinal axis. The tissue stop is disposed adjacent a distalportion of the first jaw member and is configured to impede tissue fromdistally escaping the jaw members.

The present disclosure also relates to a cartridge assembly for use witha surgical instrument. The cartridge assembly comprises a cartridge anda tissue stop. The cartridge includes a tissue contacting surface. Thetissue stop is disposed in mechanical cooperation with a distal portionof the cartridge and is configured to impede tissue from distallyescaping the jaw members. The tissue stop is movable from a firstposition wherein an upper surface of the tissue stop protrudes above thetissue contacting surface of the cartridge, and a second positionwherein the upper surface is substantially flush with the tissuecontacting surface of the cartridge.

The present disclosure also relates to a dynamic clamping member for usewith a surgical instrument. The dynamic clamping member comprises anupper beam, a lower beam, and a vertical beam. The vertical beamconnects the upper beam and the lower beam and includes a cutting edgeon a distal portion thereof. The dynamic clamping member is asymmetricalabout at least one of a vertical axis extending between a transversecenter of the upper beam and a transverse center of the lower beam, anda horizontal axis extending transversely through a vertical center ofthe vertical beam. The horizontal axis is substantially perpendicular tothe vertical axis.

BRIEF DESCRIPTION OF FIGURES

Various embodiments of the presently disclosed surgical instrument aredisclosed herein with reference to the drawings, wherein:

FIG. 1 is a perspective view of a surgical stapling instrument includinga loading unit in accordance with the present disclosure;

FIG. 1A is a perspective view of another type of surgical staplinginstrument including the loading unit of FIG. 1 in accordance with anembodiment of the present disclosure;

FIG. 2 is a perspective view of a handle assembly of the surgicalstapling instrument of FIG. 1A;

FIG. 3 is a perspective view of the loading unit of FIGS. 1 and 1A;

FIG. 4 is an enlarged view of the area of detail of FIGS. 1 and 1A;

FIG. 5 is a top view of the loading unit of FIGS. 3 and 4;

FIG. 6 is a side view of the loading unit of FIGS. 3-5, illustrated witha cartridge assembly in the open position;

FIG. 7 is a perspective, partial cross-sectional view of the loadingunit of FIGS. 3-6;

FIG. 8 is a transverse cross-sectional view of the loading unit of FIGS.3-7;

FIG. 9 is a longitudinal cross-sectional view of a portion of theloading unit of FIGS. 3-8;

FIG. 10 is a perspective assembly view of the loading unit of FIGS. 3-9;

FIG. 11 is a perspective view of a drive assembly and dynamic clampingmember of the loading unit of FIGS. 3-10;

FIG. 12 is an enlarged view of the area of detail of FIG. 11;

FIG. 13 is a perspective assembly view of the drive assembly and dynamicclamping member of FIGS. 11 and 12;

FIGS. 14-17 are various views of the dynamic clamping member accordingto an embodiment of the present disclosure;

FIG. 17A is a rear view of another embodiment of a dynamic clampingmember according to another embodiment of the present disclosure;

FIG. 17B is a perspective view of another embodiment of a dynamicclamping member according to another embodiment of the presentdisclosure;

FIGS. 18-20 are various views of an actuation sled in accordance with anembodiment of the present disclosure;

FIGS. 21 and 22 are perspective views of staples and staple pushers inaccordance with embodiments of the present disclosure;

FIGS. 23-25 are perspective views of various staple pushers inaccordance with embodiments of the present disclosure;

FIG. 26 is a perspective view of a tissue stop for use with the loadingunit of FIGS. 3-10;

FIG. 27 is a cross-sectional view of the tissue stop of FIG. 26 coupledto the loading unit; and

FIGS. 28-30 are perspective views of the loading unit of FIGS. 3-10interacting with a layer of tissue at various stages of operation of theloading unit.

DETAILED DESCRIPTION

Embodiments of the presently disclosed surgical instrument, and loadingunit for use therewith, are described in detail with reference to thedrawings, wherein like reference numerals designate correspondingelements in each of the several views. As is common in the art, the term‘proximal” refers to that part or component closer to the user oroperator, e.g., surgeon or physician, while the term “distal” refers tothat part or component farther away from the user.

A first type of surgical stapling instrument of the present disclosureis indicated as reference numeral 10 in FIG. 1. Another type of surgicalstapling instrument of the present disclosure is indicated as referencenumeral 10 a in FIGS. 1A and 2. Additionally, while not explicitlyshown, the present application also relates to surgical staplinginstruments having parallel jaw members and to electrosurgicalinstruments used to join tissue. Collectively, all surgical instruments(including surgical stapling instruments 10 and 10 a) are referred toherein as “surgical instrument” and referred to as reference numeral 10.Similarly, several features that are common to both surgical staplinginstruments are collectively referred to as the same reference number(e.g., handle assembly 12, rotation knob 14, and endoscopic portion 18).Further details of an endoscopic surgical stapling instrument aredescribed in detail in commonly-owned U.S. Pat. No. 6,953,139 toMilliman et al., the entire contents of which are hereby incorporated byreference herein.

A loading unit (or “DLU”) 500 for use with surgical instrument 10 isshown in FIGS. 3-10 and 28-30. DLU 500 is attachable to an elongated orendoscopic portion 18 of surgical instrument 10, e.g., to allow surgicalinstrument 10 to have greater versatility. DLU 500 may be configured fora single use, and/or may be configured to be used more than once.Examples of loading units for use with a surgical stapling instrumentare disclosed in commonly-owned U.S. Pat. No. 5,752,644 to Bolanos etal., the entire contents of which are hereby incorporated by referenceherein.

DLU 500 includes a proximal body portion 502 and a tool assembly 504.Proximal body portion 502 defines a longitudinal axis “A-A,” and isreleasably attachable to a distal end of elongated body portion 18 ofsurgical instrument 10. Tool assembly 504 includes a pair of jaw membersincluding an anvil assembly 506 and a cartridge assembly 508. One jawmember is pivotal in relation to the other. In the illustratedembodiments, cartridge assembly 508 is pivotal in relation to anvilassembly 506 and is movable between an open or unclamped position (e.g.,FIGS. 4 and 6) and a closed or approximated position (e.g., FIG. 8).Cartridge assembly 508 is urged in the open position via a biasingmember, e.g., a pair of compression springs 533 disposed between anvilcover 510 and cartridge 518 (see FIG. 10).

With reference to FIGS. 1 and 10, for example, tool assembly 504 has apair of jaws including anvil assembly 506 and cartridge assembly 508. Asshown, each of anvil assembly 506 and cartridge assembly 508 islongitudinally curved. That is, anvil assembly 506 and cartridgeassembly 508 are curved with respect to the longitudinal axis “A-A”defined by proximal body portion 502. The term “distal” typically refersto that part or component of the instrument that is farther away fromthe user. As used herein, the terms “distal” and “proximal” will takeinto account the curvature of curved parts of the surgical instrument 10of the present disclosure. For example, “distal” will refer to theportion of the curved part that is farthest from the user, along atrajectory defined by the curved part, such as trajectory C-C shown inFIG. 4. That is, while an intermediate portion of a curved part may befarther from the user during use, the portion of the curved part that isfarthest along its longitudinal axis is considered “distal.” Anvilassembly 506 has a proximal end 506 a and a distal end 506 b andcartridge assembly 508 has a proximal end 508 a and a distal end 508 b.

In certain embodiments, the radius of curvature of both anvil assembly506 and cartridge assembly 508 is between about 1.00 inches and about2.00 inches, and in particular, may be approximately 1.40 inches. Thecurved jaw members, as compared to straight jaw members, may helpfacilitate access to lower pelvis regions, e.g., during lower anteriorresection (“LAR”). Additionally, the inclusion of curved jaw members mayallow increased visualization to a surgical site and may also allow moreroom for a surgeon to manipulate target tissue or the jaw membersthemselves with his or her hand.

With reference to FIG. 10, anvil assembly 506 includes a cover and ananvil that are formed as an anvil cover 510 that is curved with respectto the longitudinal axis A-A, and an anvil plate 512 that is curved withrespect to the longitudinal axis A-A, which includes a plurality ofstaple forming depressions 514 (FIG. 9). Anvil plate 512 is secured toan underside of anvil cover to define a channel 511 (FIG. 8) betweenplate 512 and cover 510. When tool assembly 504 is in the approximatedposition (FIG. 8), staple forming depressions 514 are positioned injuxtaposed alignment with cartridge assembly 508.

Cartridge assembly 508 includes a curved carrier 516 that is curved withrespect to the longitudinal axis and which receives a curved cartridge518 via a snap-fit connection. Cartridge 518 includes a pair of supportstruts 524 which rest on sidewalls 517 of carrier 516 to stabilizecartridge 518 on carrier 516. Support struts 524 also set the height orlocation of cartridge 518 with respect to anvil plate 512. An externalsurface of carrier 516 includes an angled cam surface 516 a.

Cartridge 518 defines a plurality of laterally spaced staple retentionslots 528, which are configured as holes in tissue contacting surface540 (see FIG. 7). Each slot 528 is configured to receive a staple 530therein. Cartridge 518 also defines a plurality of cam wedge slots 529(see FIG. 9) which accommodate staple pushers 532 and which are open onthe bottom (i.e., away from tissue contacting surface 540) to allow alongitudinally curved actuation sled 536 to pass therethrough.

Staple cartridge 518 includes a central slot 526 that is curved withrespect to the longitudinal axis A-A, and three curved rows of stapleretention slots 528 positioned on each side of curved longitudinal slot526 (see FIGS. 7 and 8). More specifically, actuation sled 536 passesthrough cam wedge slots 529 and forces staple pushers 532 towardsrespective staples 530. The staples are then forced out of theirrespective staple retention slots 528.

With reference to FIGS. 21 and 22, pushers 532 of the illustratedembodiments each engage two or more staples 530. Pushers 532 include asingle distally-located triple pusher 532 a (FIG. 23), a singleproximally-located double pusher 532 b (FIG. 24), and a series of triplepushers 532 c (one triple pusher 532 c is shown in FIG. 25) which extendbetween double pusher 532 b and triple pusher 532 a on each side of slot526. In disclosed embodiments, portions of pushers 532 a, 532 b, 532 care curved, or the pusher plates that support the surgical staples areoffset or angled with respect to one another. In certain embodiments, atleast some of the pushers 532 a, 532 b, 532 c include no curved surfacesand the pusher plates that support and drive the surgical staples areangled with respect to one another.

During operation of stapler 10, actuation of its movable handle 22through successive strokes causes distal advancement of its drive bar 30(a distal portion of which is illustrated in FIG. 2), such that drivebar 30 pushes a drive assembly 560 through cartridge 518. (Furtherdetails of how actuation of movable handle 22 causes distal advancementof drive bar 30 are explained in U.S. Pat. No. 6,953,139 to Milliman etal., which has been incorporated by reference herein.) The movement ofdrive assembly 560, and in particular, a dynamic clamping member 606affixed thereto, moves a longitudinally curved actuation sled 536 (seeFIGS. 18-20) through cartridge 518. As sled 536 moves through cartridge518, longitudinally curved cam wedges 534 of actuation sled 536sequentially engage pushers 532 to move pushers 532 vertically withinstaple retention slots 528 and eject staples 530 into staple formingdepressions 514 of anvil plate 512. Subsequent to the ejection ofstaples 530 from retention slots 528 (and into tissue), a cutting edge606 d of dynamic clamping member 606 severs the stapled tissue ascutting edge 606 d travels through curved slot 526 of cartridge 518.

Referring to FIG. 8 and in accordance with embodiments of the presentdisclosure, cartridge 518 includes a tissue contacting surface 540including surfaces 540 a, 540 b, and 540 c. Surface 540 a is adjacentlongitudinal slot 526 and defines a first gap between tissue contactingsurface 540 and a bottom surface 544 of anvil plate 512. Surface 540 bis located adjacent surface 540 a and defines a second gap betweentissue contacting surface 540 and bottom surface 544. Surface 540 c islocated proximal to an outer perimeter of cartridge 518 and defines athird gap between tissue contacting surface 540 and bottom surface 544.The first gap is less than the second gap, which is less than the thirdgap. When anvil 506 is approximated towards cartridge 508, layers oftissue located between bottom surface 544 and tissue contacting surface540 are compressed. Since the first gap is the smallest, tissue locatedbetween surface 540 a and bottom surface 544 is compressed the most.Similarly, the tissue located between surface 540 c and bottom surface544 is compressed the least, with the tissue located between surface 540b and bottom surface 544 being compressed to an intermediate degree. Thearrangement of surfaces 540 a, 540 b, 540 c on tissue contacting surface540 provides a tissue compression gradient extending transverse to alongitudinal axis of the cartridge 518.

Referring to FIGS. 8, 21 and 22 in conjunction with the steppedarrangement of tissue contacting surface 540, the illustrated embodimentof staples 530 include varying leg lengths for cooperating with thevarying gaps. Staples 530 a have the shortest leg length and areassociated with surface 540 a. Similarly, staples 530 b have anintermediate leg length and are associated with surface 540 b, whilestaples 530 c have the longest leg length and are associated withsurface 540 c. The leg length of staples 530 b is between the leg lengthof staples 530 a and 530 c. Since the tissue between surface 540 a andbottom surface 544 has been compressed the most, the resulting thicknessof the tissue is at a minimum, thereby allowing a staple having ashorter leg length (i.e. staple 530 a) to be used to join the layers oftissue. The layers of tissue between surface 540 b and bottom surface544 are compressed to an intermediate degree of compression and theresulting thickness of the tissue layers allows a staple having anintermediate leg length (i.e. staple 530 b) to be used when joining thelayers of tissue. The layers of tissue between surface 540 c and bottomsurface 544 are compressed the least amount and are thicker than theother layers requiring staples that have the longest leg length (i.e.staples 530 c) for joining the layers of tissue.

In particular, the illustrated embodiment of pusher 532 includes plates531 a, 531 b, 531 c, which cooperate with staples 530 a, 530 b, 530 c,respectively. Plate 531 a has a height which is greater than the heightof plate 531 b. Additionally, the height of plate 531 b is greater thanthe height of plate 531 c. Pusher 532 further includes cam members 542that are longitudinally staggered. As sled 536 translates distallythrough cartridge 518, cam wedges 534 engage cam members 542 of pusher532, thereby urging pusher 532 in a direction transverse to thelongitudinal axis of cartridge 518 and urging staples 530 towards stapleforming depressions 514 of anvil plate 512. In particular, cam wedges534 are longitudinally staggered such that when they engage staggeredcam members 542, the resulting forces applied to move pusher 532 towardstissue contacting surface 540 are evenly applied.

With continued reference to FIGS. 21 and 22, staples 530 a, 530 b, 530 cride on pusher 532 (for illustrative purposes, pusher 532 c from FIG. 25is shown). Additionally, cam members 542 of each pusher 532 include camsurfaces 542 a and 542 b. Each cam surface 542 a, 542 b is configured tobe contacted by cam wedges 534. In particular, and with reference toFIGS. 21-25, cam wedges 534 a are configured to cam surfaces 542 a; camwedges 534 b are configured to engage cam surfaces 542 b; centralsection 534 c of sled 536 is configured to travel through slot 526.

Referring to FIG. 20, the illustrated embodiment of actuation sled 536includes a curved projection 535 depending from a lower surface thereof.Projection 535 is configured to travel within a slot 515 (FIG. 10) ofcarrier 516.

With reference to FIG. 10, proximal body portion 502 includes an innerbody 503 formed from molded half-sections 503 a and 503 b, a driveassembly 560 and a drive locking assembly 564. Proximal body portion 502is coupled to tool assembly 504 by a mounting assembly 570. Mountingassembly 570 has a pair of extensions 576 which extend into a proximalend of carrier 516. Each extension 576 has a transverse bore 578 whichis aligned with a hole 580 in the cartridge 518 such that mountingassembly 570 is pivotally secured to cartridge 518 by pin 582. Mountingassembly 570 is fixedly secured to half-section 503 a by a pair ofvertical protrusions 584. Vertical protrusions 584 extend upwardly frommounting assembly 570 and frictionally fit into corresponding recesses(not shown) in half-section 503 a.

With continued reference to FIG. 10, the illustrated embodiment of anvilcover 510 includes a proximally extending finger 588 having a pair ofcutouts 590 formed therein. Cutouts 590 are positioned on each lateralside of finger 588 to help secure anvil cover 510 to half-section 503 a.More particularly, half-section 503 a includes a channel 505 therein,and channel 505 includes a pair of protrusions 505 a. Finger 588 ofanvil cover 510 mechanically engages channel 505 of half-section 503 a,such that cutouts 590 are aligned with protrusions 505 a. An outersleeve 602 covers the finger and channel. The configuration of finger588 and channel 505 facilitates a secure connection between anvil cover510 and half-section 503 a. Moreover, this connection results in anon-movable (e.g., non-pivotable) anvil assembly 506 with respect toproximal body portion 502.

Referring to FIGS. 11-13, drive assembly 560 includes a flexible drivebeam 604 which is constructed from three stacked metallic sheets 604 a-cand a proximal engagement portion 608. At least a portion of drive beam604 is sufficiently flexible to be advanced through the curvature of thetool assembly 504. Drive beam 604 has a distal end which is secured to adynamic clamping member 606 via a butt weld 606 f (FIG. 12), spot weld,adhesive, joint or other connection. Spot welds 606 h, which areconfigured to hold sheets 604 a-c together, are also shown in FIG. 12.

Engagement section 608 is fastened to a proximal portion of middle sheet604 b (e.g., via a butt weld) and includes a stepped portion defining ashoulder 610. A proximal end of engagement section 608 includesdiametrically opposed inwardly extending fingers 612. Fingers 612 engagea hollow drive member 614 to fixedly secure drive member 614 to theproximal end of beam 604. Drive member 614 defines a proximal porthole616 which receives the distal end of a control rod of drive bar 30 (seeFIG. 2) when DLU 500 is attached to surgical stapling instrument 10.

With reference to FIGS. 14-17, dynamic clamping member 606 includes avertical strut or vertical portion 606 a, an upper beam 606 b and alower beam 606 c. A knife or cutting edge 606 d is formed on a distalface of vertical strut 606 a. As illustrated, the width of verticalstrut 606 a is equal to the width of drive beam 604 of drive assembly560 (see FIG. 12). With particular reference to FIG. 16, vertical strut606 a and knife 606 d are longitudinally curved from a first lateralside 606 e of clamping member towards a second lateral side 606 f ofclamping member 606. Both upper beam 606 b and lower beam 606 c arelinearly disposed with respect to longitudinal axis “A-A.”

As illustrated in FIGS. 14-17 A, the present disclosure includesembodiments of dynamic clamping member 606 that are asymmetrical. Forinstance, in the embodiment illustrated in FIGS. 15 and 17, lower beam606 c is larger in height than upper beam 606 b. In this embodiment,dynamic clamping member 606 is asymmetrical about horizontal axis “H-H”extending through the center of the vertical portion or strut, asillustrated in FIG. 17. It is envisioned that lower beam 606 c includesa height “TL”• It is envisioned that upper beam 606 b includes a height“Tu”.

An additional example of an asymmetrical dynamic clamping member 606 isalso illustrated in FIG. 17. In this embodiment, the transversecross-sectional shape of upper beam 606 b includes an upper planarsurface 606 b 1 and a lower planar surface 606 b 2. The cross-sectionalshape of lower beam 606 c includes an upper planar surface 606 c 1 and alower arcuate surface 606 c 2. In this embodiment, dynamic clampingmember 606 is asymmetrical about the horizontal axis “H-H.”

The embodiment shown in FIGS. 16 and 17 illustrates distal portion ofvertical portion or strut 606 a being off-center with respect to theremainder of clamping member 606 so that the cutting edge facesoff-center with respect to an axis B-B through the clamping member 606.In certain embodiments, the upper beam and lower beam are polygonal inshape and not curved. For example, the upper beam and lower beam can berectangular, as seen in FIG. 16. In other embodiments, the upper beamand/or lower beam can be formed from a pin or roller mounted in thevertical portion. In this embodiment, dynamic clamping member 606 isasymmetrical about vertical axis “V-V” illustrated in FIG. 17.

With reference to FIG. 17A, dynamic clamping member 606′ is shown. Lowerbeam 606 c′ is wider than upper beam 606 b′ of dynamic clamping member606′. More particularly, it is envisioned that a width “wl” of lowerbeam 606 c′ is between about 0.180 inches and about 0.200 inches, andthat a width “wu” of upper beam 606 b′ is between about 0.160 inches andabout 0.180 inches. In this embodiment, dynamic clamping member 606′ isasymmetrical about the horizontal axis “H-H.” Further, while notexplicitly shown, it is envisioned that upper beam 606 b′ is wider thanlower beam 606 c′ of a dynamic clamping member 606 of the presentdisclosure. Additionally, dynamic clamping member 606′ is shown as beinglongitudinally linear (vis-à-vis longitudinally curved), in accordancewith embodiments of the present disclosure.

The asymmetrical embodiments of dynamic clamping member 606 of thepresent disclosure help ensure proper orientation of dynamic clampingmember 606 during assembly of surgical stapling instrument 10 or DLU500. That is, the asymmetry of dynamic clamping member 606 preventsdynamic clamping member 606 from improper placement with respect to toolassembly 504, since dynamic clamping member 606 can only physically fitin a particular orientation. In particular, the asymmetry ensures thatknife 606 d faces distally and is positioned to travel through the spacebetween cartridge assembly 508 and anvil assembly 506, for example.

With reference to FIG. 17B, the present disclosure includes anotherembodiment of a dynamic clamping member 606″ that is also configured tohelp ensure proper orientation of dynamic clamping member 606″ duringassembly of surgical stapling instrument 10 or DLU 500. Dynamic clampingmember 606″ includes a protrusion 607 extending from a proximal surface606 i thereof. In the illustrated embodiment, a drive assembly 560″ hasa smaller height than embodiment of drive assembly 560′ illustrated inFIGS. 10-13. Protrusion 607 is shown being disposed on a lower portionof dynamic clamping member 606″ (i.e., on the opposite side as cuttingedge 606 d″) and to one side of drive assembly 560″, but it isenvisioned that protrusion 607 is disposed on the other side of driveassembly 560″.

As discussed above, the inclusion of protrusion 607 helps ensure properorientation of dynamic clamping member 606″. More particularly, it isenvisioned that extensions 576 of mounting assembly 570 would physicallyprevent further assembly of dynamic clamping member 606″ beingincorrectly fastened to drive assembly 560″ (e.g., when dynamic clampingmember 606″ is up-side-down with respect to drive assembly 560″.

It is further envisioned that dynamic clamping member 606, 606′ mayinclude any combination of the asymmetrical features discussed hereinand may also include protrusion 607 of dynamic clamping member 606″.

With additional reference to dynamic clamping member 606 of FIGS.14-17A, it is envisioned that each of upper beam 606 b and 606 cincludes a plastic material or layer which is injection molded onto anoutwardly facing surface of each beam 606 b and 606 c. Plastic layerprovides reduced frictional engagement between dynamic clamping member606 and cartridge and anvil assemblies 508 and 506, respectively, duringactuation of tool assembly 504.

Referring back to FIG. 8, channel 511 is configured and dimensionedaccordingly to accommodate a corresponding embodiment of upper beam 606b of clamping member 606; slot 526 is configured and dimensionedaccordingly to accommodate a corresponding embodiment of vertical strut606 a of clamping member 606. As can be appreciated, when used with theembodiment of dynamic clamping member 606 of FIG. 17A, channel 511 istoo narrow to accommodate lower beam 606 c of dynamic clamping member606.

With reference to FIG. 10, when drive assembly 560 is advanced distallywithin tool assembly 504, upper beam 606 b moves within channel 511defined between anvil plate 512 and anvil cover 510, and lower beam 606c moves over an exterior surface of carrier 516. When lower beam 606 cengages and moves over cam surface 516 a, cartridge assembly 508 pivotsfrom the open position to the closed position. As dynamic clampingmember 606 continues to move distally along and through tool assembly504, the maximum gap between anvil plate 512 and cartridge 518 isdefined by engagement of layer 606 e on upper beam 606 b (FIG. 12) and alower surface defining channel 511, and engagement of a layer 606 g onlower beam 606 c with the external surface of carrier 516. In disclosedembodiments, the height of channel 511 is greater than the height ofupper beam 606 b, providing clearance between the upper surface ofdynamic clamping member 606 and the anvil plate 512 so that upper beam606 b of dynamic clamping member 600 does not simultaneously engage theupper and lower surfaces of anvil channel 511.

With continued reference to FIG. 10, DLU 500 includes a lockingmechanism 564 including a locking member 620 and a locking memberactuator 622. Locking member 620 is rotatably supported within alongitudinal or axial slot 625 formed in a proximal portion of an upperhousing half 503 a of inner body 503 of DLU 500. Locking member 620 ismovable from a first position, in which locking member 620 maintainsdrive assembly 560 in a prefired position, to a second position in whichdrive assembly 560 is free to move axially.

Locking member 620 includes a semi-cylindrical body 624 which isslidably positioned within transverse slot 625 formed in upper housinghalf 503 a of body portion 503. Body 624 includes a radially inwardlyextending cam member 628 and a radially inwardly extending finger 630.Finger 630 is dimensioned to be received within a notch 632 formed indrive assembly 560. Engagement of finger 630 in notch 632 of driveassembly 560 prevents drive assembly 560 from moving linearly withinbody portion 503 to prevent actuation of DLU 500 prior to attachment ofDLU 500 to surgical instrument 10.

Locking member actuator 622 is slidably positioned within axial slot 625formed in upper housing half section 503 a of body portion 503 of DLU500. Actuator 622 includes a proximal abutment member 636, a distalspring guide 627, and a central cam slot 640. Axial slot 641 in thehousing half section 503 a intersects transverse slot 625 such that cammember 628 of locking member 620 is slidably positioned within cam slot640 of locking member actuator 622. A biasing member or spring 642 ispositioned about spring guide 627 between a distal surface of actuator622 and a wall 641 a defining the distal end of axial slot 641. Spring642 urges actuator 622 to a first position within axial slot 641. In thefirst position, abutment member 636 is positioned on insertion tip 650of proximal body portion 502 (FIG. 3) and cam slot 640 is positioned tolocate cam member 628 such that finger 630 of lock member 620 ispositioned within notch 632 of drive assembly 560.

Prior to attachment of DLU 500 onto surgical instrument 10, spring 642urges actuator 622 to the first position to maintain the lock member 620in its first position as discussed above. When insertion tip 650 of DLU500 is linearly inserted into the open end of the body portion 18 (FIG.2) of surgical instrument 10, nubs 652 of insertion tip 650 (FIG. 3)move linearly through slots (not shown) formed in open end of bodyportion 18. As nubs 652 pass through the slots, the proximal end ofabutment member 636, which is angularly offset from nubs 652, abuts awall defining the slots for receiving nubs. As DLU 500 is moved fartherinto body portion, locking member actuator 622 is moved from its firstposition to its second position. As actuator 622 is moved to its secondposition, lock member 620 is cammed from its first position engaged withnotch 632 of drive assembly 560 to its second position to move finger630 from notch 632. The locking mechanism including locking member 620and locking member actuator 622 prevents advancement of the driveassembly 560 of DLU 500 prior to loading of DLU 500 onto a surgicalinstrument 10.

In the embodiments illustrated in FIGS. 3 and 10, locking memberactuator 622 includes an articulation lock portion 637 disposed thereon.In particular, articulation lock portion 637 extends in an approximateright angle from abutment member 636. Articulation lock portion 637 isconfigured to physically prevent the longitudinal translation of anarticulation member (not shown) of a handle portion of a surgicalinstrument having articulation capabilities. That is, even when DLU 500is engaged with a surgical instrument 10 that is otherwise capable ofarticulation (i.e., pivotable movement of the jaw members with respectto the elongated portion 18), articulation lock portion 637 of DLU 500prevents an articulation member from entering DLU 500.

Referring to FIG. 10, upper half-section 503 a of proximal body portion502 defines a longitudinal slot 660 which receives a leaf spring 662.Leaf spring 662 is confined within slot 660 by outer sleeve 602. Leafspring 662 has an angled proximal end 664 which is positioned to abutshoulder 610 (FIG. 11) of engagement section 608 of drive beam 604 whendrive beam 604 is in its refracted position. When drive beam 604 isadvanced distally by advancing drive bar 30, as described above, leafspring 662 is flexed upwardly by shoulder 610 of drive beam 604 topermit distal movement of drive beam 604.

Referring to FIGS. 4, 7, and 26-30, DLU 500 also includes a tissue stop700. Tissue stop 700 includes a body 710, a pair of legs 720 extendingproximally from the body 710, a stopping portion 730, a pair oflaterally opposed protrusions 740 extending transversely from body 710(See FIG. 26), and a knife channel 750 disposed between pair of legs720. Tissue stop 700 is pivotally connected to a distal portion ofcartridge assembly 508 via the engagement between protrusions 740 and acorresponding pair of apertures (not shown) disposed within cartridgeassembly 508. Cartridge assembly 508 includes an opening 519 (FIGS. 7and 10) adapted to receive both legs 720 of tissue stop 700. A recess521 is positioned distally of opening 519 and is adapted to receive aportion of tissue stop 700 therein. The recess 521 and opening 519 areshown in FIG. 10.

Tissue stop 700 is movable between a first position (FIG. 4), whichcorresponds to when the jaw members are in an open position where anupper surface 701 thereof is disposed between cartridge assembly 508 andanvil assembly 506 (FIG. 4 illustrates the jaw members in a partiallyapproximated position; FIG. 6 illustrates the jaw members in a fullyopened position), and a second position (FIG. 30), which corresponds towhen the jaw members are in the approximated position and where uppersurface 701 of tissue stop 700 is substantially flush with tissuecontacting surface 514 of cartridge 518. (In FIG. 30, upper surface 701is hidden as upper surface 701 is within cartridge assembly 508.) Abiasing member 760 (FIG. 10), a portion of which is disposed aroundprotrusion 740, urges tissue stop 700 towards its first position. Tissuestop 700 also includes a finger 770 (FIG. 26) extending distally fromeach leg 720. With specific reference to FIG. 27, when the jaw membersare in the open position, fingers 770 of tissue stop 700 engage a lip523 disposed on cartridge assembly 508 to limit the amount of movementimparted by biasing member 760 in the general direction of arrow “B” inFIG. 27.

When tissue stop 700 is in its first position, tissue “T” is proximallyinsertable (in the general direction of arrow “A” in FIG. 28) fromdistally beyond tissue stop 700, to a location that is between anvilassembly 206 and cartridge assembly 508 and proximal of tissue stop 700(see FIGS. 28 and 29). In this position, stopping portion 730, which isdisposed at an oblique angle (e.g., between about 45° and about 90°)with respect to tissue contacting 540 of cartridge assembly 508, impedestissue from distally escaping the tool assembly 504. When the jawmembers are approximated (e.g., when cartridge assembly 508 is pivotedtowards anvil assembly 506), tissue stop 700 (or tissue “T”) contactsanvil assembly 506, thus causing tissue stop 700 to pivot from its firstposition towards its second position. Legs 720 of tissue stop 700 areconfigured to lie within opening 519 (i.e., equal to or below the tissuecontacting surface 540) of cartridge assembly 508 when tissue stop 700is in its second position, such that legs 720 do not interfere with thelocation of the tissue with respect to the cartridge assembly 508 andrespect to anvil assembly 506 (i.e., so that the staples can be deployedinto tissue lying over the tissue stop). When the cartridge assembly 508moves away from anvil assembly 506, tissue stop 700, under the influenceof biasing member 760, returns to its first position.

With additional regard to knife channel 750, knife channel 750 isconfigured to allow vertical strut 606 a (including cutting edge 606 d)of dynamic clamping member 606 to travel distally past a portion oftissue stop 700 (i.e., at least to a location adjacent the distal-mostlongitudinal slot 528). Additionally, it is envisioned that at least aportion of knife channel 750 (e.g., the portion that is contacted bycutting edge 606 d) is over molded with plastic or another suitablematerial, or the knife channel 750 has disposed therein a material forreceiving the knife blade as the knife reaches the end of its travelduring the operation of the instrument.

While not explicitly illustrated, it is also envisioned that tissue stop700 is usable with a surgical instrument having parallel jaws and/or anelectrosurgical instrument. An example of a surgical instrument havingparallel jaws is described in commonly-owned U.S. Pat. No. 7,237,708 toGuy et al., the entire contents of which are hereby incorporated byreference herein. An example of an electrosurgical instrument isdescribed in commonly-owned patent application Ser. No. 10/369,894,filed on Feb. 20, 2003, entitled VESSEL SEALER AND DIVIDER AND METHOD OFMANUFACTURING THE SAME, the entire contents of which are herebyincorporated by reference herein.

The present disclosure also relates methods of using the describedsurgical instrument 10 or DLU 500 to perform a lower anterior resection.Such a method includes providing surgical instrument 10 or DLU 500,positioning jaw members adjacent tissue, and approximating one jawmember (e.g., cartridge assembly 508) with respect to the other jawmember (e.g., anvil assembly 506). The drive assembly 560 is advancedincrementally such that dynamic clamping member 606 and at least aportion of drive assembly 560 move along a curvilinear path anincremental distance for each stroke of the movable handle. The driveassembly 560 moves distally to cause staples 530 to be ejected intotissue “T” and to cut tissue “T.” In other embodiments, the driveassembly is moved the length of the jaws of the instrument in onestroke. In other embodiments, the instrument is operated by motor orpneumatic power, rather than by manual power. In certain embodiments,the jaw members are approximated, and the interior of the intestinaltissue is then washed out or otherwise cleansed. The tissue is then cutand stapled. In this way, the interior intestinal tissue is cleansed upto the location of the jaw members. A clamp may be used to isolate aportion of the intestine for cleaning, and the clamp may comprise aseparate instrument, or may be incorporated in the surgical staplinginstrument or loading unit.

The present disclosure also relates to methods of assembling surgicalinstrument 10 or DLU 500. Such a method includes positioningasymmetrical dynamic clamping member 606, 606′ in mechanical engagementwith a portion of tool assembly 504, and wherein the positioning stepautomatically results in the proper positioning of asymmetrical dynamicclamping member 606. In another embodiment, the clamping member ispositioned with respect to the anvil assembly and the fit of theclamping member with the anvil assembly is determined. If the clampingassembly does not initially fit, the clamping assembly is rotated 180degrees. Another method includes attaching dynamic clamping member 606″to drive assembly 560″ in a way that would enable fail-safe positioningof dynamic clamping member 606″ with respect to tool assembly 504.

In certain embodiments of the present disclosure, a surgical staplinginstrument as discussed above has a replaceable cartridge rather than areplaceable loading unit with a complete tool assembly having a pair ofjaws. The jaws of the surgical stapling instrument are attached to theendoscopic portion and handle and include a channel for receiving thereplaceable cartridge. The cartridge is an assembly having a tissue stopincorporated with the cartridge assembly. The tissue stop may otherwisebe as described above.

While the above description contains many specifics, these specificsshould not be construed as limitations on the scope of the presentdisclosure, but merely as illustrations of various embodiments thereof.Therefore, the above description should not be construed as limiting,but merely as exemplifications of various embodiments. Those skilled inthe art will envision other modifications within the scope and spirit ofthe claims appended hereto.

The invention claimed is:
 1. A surgical stapling instrument, comprising:an endoscopic portion; and a tool assembly extending generally distallyfrom the endoscopic portion, the tool assembly having a pair of jawmembers and a drive assembly disposed for movement through the jawmembers, at least one of the jaw members being movable with respect tothe other between an open position and an approximated position forengaging body tissue therebetween, the drive assembly including adynamic clamping member having an upper beam, a lower beam, and avertical beam, the upper beam having an upper surface and a lowersurface where a distance between the upper surface and the lower surfacedefines an upper beam height, and the lower beam having a lower beamupper surface and a lower beam lower surface where a distance betweenthe lower beam upper surface and the lower beam lower surface defines alower beam height, the upper beam height being less than the lower beamheight.
 2. The surgical stapling instrument according to claim 1,wherein the cross-sectional shape of the lower beam is different thanthe cross sectional shape of the upper beam.
 3. The surgical staplinginstrument according to claim 1, wherein the upper beam, lower beam, orboth, include a plastic material.
 4. The surgical stapling instrumentaccording to claim 1, wherein the drive assembly includes a flexibledrive beam.
 5. The surgical stapling instrument according to claim 4,wherein the dynamic clamping member is integrally formed and attached tothe drive beam at a distal end thereof.
 6. The surgical staplinginstrument according to claim 4, wherein the drive beam includes aplurality of sheets.
 7. The surgical stapling instrument according toclaim 6, wherein the drive beam includes an engagement section fastenedto one of the sheets.
 8. The surgical stapling instrument according toclaim 1, wherein the dynamic clamping member includes a knife.
 9. Thesurgical instrument of claim 1, wherein each of the jaw members iscurved with respect to the first longitudinal axis.
 10. The surgicalstapling instrument according to claim 1, wherein the tool assemblyincludes a tissue stop at a distal end of the pair of jaw members. 11.The surgical stapling instrument according to claim 1, wherein one ofthe pair of jaw members is a cartridge assembly having a plurality ofsurgical staples.
 12. The surgical stapling instrument according toclaim 11, wherein the other of the pair of jaw members is an anvilassembly.
 13. The surgical stapling instrument according to claim 12,wherein the drive assembly can be engaged in the jaw members in only oneorientation of the drive assembly.
 14. The surgical stapling instrumentaccording to claim 1, wherein the tool assembly is part of a loadingunit that can be removably attached to the endoscopic portion.